A viscoelastic body is useful as a material for a pressure-sensitive adhesive, and has been actively researched and developed in various industrial fields, by virtue of its excellent balance between elasticity and viscosity (see Patent Literature 1). Because of its low modulus, a pressure-sensitive adhesive formed of the viscoelastic body becomes wet to conform to an adherend, thereby expressing its pressure-sensitive adhesive strength.
Hitherto, an acrylic resin, a rubber-based resin, a silicone-based resin, or the like has been generally used as the material for a pressure-sensitive adhesive.
Meanwhile, a fibrous columnar structure having a fine diameter has been known to exhibit pressure-sensitive adhesive property. It has been elucidated that the structure follows surface unevenness of an adherend to express its adhesive strength by virtue of a van der Waals force because the structure has a diameter of the order of from micrometers to nanometers.
A carbon nanotube as the fibrous columnar structure has been reported to exhibit pressure-sensitive adhesive property (see Patent Literature 2 and Patent Literature 3). It has been elucidated that the carbon nanotube follows the surface unevenness of the adherend to exhibit its pressure-sensitive adhesive strength by virtue of the van der Waals force because the carbon nanotube has a nanoscale diameter.
In recent years, there is a demand for means for allowing a particle having a specified particle diameter to be selectively acquired from a particle group with a large particle diameter distribution in some cases.
However, in a related-art viscoelastic body, it is difficult to selectively pick a particle having a specified particle diameter from a particle group with a large particle diameter distribution. In addition, the related-art viscoelastic body is difficult to handle because it easily adheres to a smooth surface owing to its strong tack.